'Beautiful nightmare' crab with cartoonish eyes discovered

By Lindsey Bever

April 26, 2019 — 2.53pm

Scientists have discovered a species of crab that swam in the sea 95 million years ago.

The small, pocket-size crab, named Callichimaera perplexa, was very different from its modern-day cousins. It sported a tiny lobster-like shell, legs flattened like oars and huge, Pound Puppies' eyes that protruded from its head, which, researchers said, show that the creature used its eyes actively for whatever it did for a living.

An artist's reconstruction of Callichimaera perplexa.Credit:Oksana Vernygora/University of Alberta

But it's not only the creature's cartoon appearance that has some researchers tickled, it's also what the ancient animal means to science.

Javier Luque, a postdoctoral palaeontologist at both Yale University and the University of Alberta, said the "cute" and "unusual" decapod crustacean was going to make scientists "rethink what a crab is."

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"It gives us information about how novel body forms can evolve over time," Luque said in an interview with The Washington Post on Thursday.

Luque said he made the discovery in the mountains in Pesca, Boyaca, in Colombia in 2005.

An artistic reconstruction of Callichimaera perplexa.Credit:Oksana Vernygora/University of Alberta

Luque, who was an undergraduate geology student at the time, said he was hunting for fossils when he uncovered a trove of specimens from crustaceans - shrimp, lobsters and crabs with big, bulbous eyes.

Luque and his research team, who have been studying the well-preserved fossils found in Colombia and the United States, published their findings in the journal Science Advances on Wednesday.

The research provides insight into a creature so peculiar that it has been dubbed "the platypus of the crab world".

So what do we know about this wide-eyed critter?

The crab lived during the mid-Cretaceous period - when dinosaurs ruled the earth, land masses were in motion and the oceans were taking shape. And based on where the fossils were found, it lived in what is now Colombia, northern Africa and the United States, more specifically, Wyoming.

Its name, Callichimaera perplexa, means "perplexing beautiful chimera", an allusion to a Greek mythological creature that had body parts from different animals. Makes sense. Luque said researchers believe the crab had a "mosaic of body parts", including unprotected compound eyes, a spindle-shaped body and leg-like mouth parts that suggest it retained larval traits into adulthood.

The crab's body had a diameter of about 2.5 centimetres.

Its eyes were so large that, had it been a human, it would have had eyeballs as big as soccer balls.

Its legs were built for swimming, rather than crawling.

Its wrench-like claws made it a powerful little hunter.

And, had the crab lived another 95 million years or so, it most likely would have made it to Hollywood.

Luque, the lead author of the study, told Live Science that "I call it my beautiful nightmare because it was so beautiful and frustrating" for the researchers to comprehend.

Heather Bracken-Grissom, an evolutionary biologist at Florida Internal University who specialises in decapods, said that more than 7000 species of crabs were living today.

This "bizarre find" would allow scientists to re-evaluate what they know about them, she said.

"This new transitional fossil is making us rethink how crabs have evolved over time because it's introducing this unique body form we weren't aware of before," she said.

She said that it revealed "an early lineage in the crab tree of life".